New synthetic methods, designed for the elaboration of complex natural products, are being developed and applied to the total syntheses of biologically active compounds. The treatment of propargyl alcohols with amide acetals and related reagents has revealed a number of new reactions; the scope and mechanism of each of these transformations is being investigated. The requirements for the intramolecular Diels-Alder reaction of the furan nucleus are being elucidated. Direct approaches to the construction of 1,4 benzodiazepine antibiotics are being explored.